While the setting is modern Tokyo, in reality that's a city I've only visited briefly. Even though I occasionally travel to Japan I remain a tourist there, and thus, what I describe will remain a fantasy based on generic depictions from other works. Names for places in Japan (schools included) are created out of thin air, so don't bother trying to find them in real life. Don't worry, neither will I.
The same isn't entirely true for Sweden, even though I'll never allow reality to stand in the way for the story. If a landmark monument was erected last year, but I need it in place ten years ago, rest assured it'll be eleven years old in my story.
Anyway, I do, however, have a connection to Japan. 50% of me to be more exact. So I'm playing around with the Sweden I've known for my entire life, the lessons I've learned from my mother (that would be the 100% Japanese part who gave life to your scribe) and my own overall experience of life.
Have I based things on myself? Of course, and friends, and people I just found interesting. As the author I'll also embellish those parts I like, and hide those I'm too embarrassed to admit are part of me. And, obviously, whenever there's a positive trait I lack, I'll simply rewrite history and invent it as needed.
Even though both Swedes in the main cast have borrowed a lot of traits of mine and some from those close to me, the only real individual any character is resembling is myself. Last I checked that doesn't count as libel.
The story as such will, to a great degree, be based upon Swedish sensibilities. While I'm as subjective as anyone else, I'll make an attempt to balance what I find attractive with both cultures. In difference from the authors/editors/market-demands of the manga/anime I've read/watched I'm perfectly aware that Sweden isn't the centre of the universe. I'll use this, and twist it, to produce a broken glass through which I look at both Sweden and Japan.
My characters, however, can't be trusted.